Amorim Fraga, Mariana (2015): Talking about Carbon-based films and their use as piezoresistive materials. figshare. https://doi.org/10.6084/m9.figshare.2056353.v1

1. Carbon-based Films as
Piezoresistive Materials
Mariana Amorim Fraga
September 2014

2. Outline
• Motivation – Why use carbon-based
films as piezoresistive materials?
• Properties of carbon-based films
• Synthesis of carbon-based films
• Application of carbon-based thin
films as sensing materials in
piezoresistive sensors

3. Motivation
Comparison - Semiconductor properties of silicon and
carbon-based materials (SiC and diamond)

4. Motivation
Comparison - Mechanical properties of silicon
and carbon-based materials (SiC, DLC and
diamond)

5. Motivation
Development of eletronic and MEMS
devices for harsh environments
• High temperature;
• High power;
• Atmosphere corrosive;

6. Properties of carbon-based films
1.Diamond
2. Diamond-like carbon (DLC)
3.Silicon Carbide (SiC)

7. Diamond – Properties

8. Diamond Films Synthesis
High pressure and high temperature
* adapted from Bachmann, P. K. 1994. Microwave plasma CVD, and related techniques for low pressure diamond synthesis.
In: Thin Film Diamond. A. Lettington and J. W. Steeds (ed.), London, Chapman and Hall, 31-53.

9. Diamond Films

10. DLC - Properties

11. DLC Films Synthesis
• PECVD (Plasma Enhanced Chemical
Vapor Deposition);
• Magnetron sputtering;
• Pulsed Laser Deposition;
• Filtered Cathodic Arc Deposition;

12. DLC Films

13. Silicon Carbide - Properties

14. SiC Films Synthesis
• PECVD (Plasma Enhanced Chemical
Vapor Deposition);
•CVD (Chemical Vapor Deposition);
• Magnetron sputtering;
• Pulsed Laser Deposition;

15. SiC Films

16. Carbon-based materials as sensing materials in
piezoresistive sensors
The gauge factor (GF) of a material is defined as the fractional change of
resistance (ΔR/R) per unit strain ε.
* Single-material MEMS using polycyrstalline diamond by Cao, Zongliang, Ph.D., Michigan State University, 2011.

17. Carbon-based materials as sensing materials in
piezoresistive sensors

18. Carbon-based materials as sensing materials in
piezoresistive sensors

19. Carbon-based materials as sensing materials in
piezoresistive sensors

20. Carbon-based materials as sensing materials in
piezoresistive sensors
Effect of temperature on piezoresistivity of diamond
• The gauge factors for p-type diamond piezoresistor are
~1000 at room temperature and > 700 at 200°C (Deguchi
et al., 2001);
•Pressure sensor using p-type polycrystalline diamond
piezoresistors exhibits 0.19% of resistance change at
room temperature. This sensitivity decreases for 0.06% at
250 ºC (Yamamoto et al., 2005);
•The gauge factors of polycrystalline diamond films
decreased with increased temperature from room
temperature to 300 °C. However, with higher temperature
up to 500 °C, it increased (Yamamoto et al., 2007).

21. References
M. A Fraga, H. Furlan, R.S. Pessoa, M. Massi, Wide bandgap semiconductor thin films for piezoelectric
and piezoresistive MEMS sensors applied at high temperatures: an overview. Microsystem
Technologies, 20, p. 9-21, 2014.
M. A. Fraga, H. Furlan, R. S. Pessoa, L. A. Rasia, C. F. R. Mateus, Studies on SiC, DLC and TiO2 thin
films as piezoresistive sensor materials for high temperature application. Microsystem Technologies, 18,
p. 1027-1033, 2012.
M. A Fraga, R.S. Pessoa, M. Massi, H.S. Maciel. Applications of SiC-Based Thin Films in Electronic and
MEMS Devices. In: Yasuto Hijikata. (Org.). Physics and Technology of Silicon Carbide Devices.
1ed.Rijeka: Intech, v. 1, p. 313-336, 2012.
M. A. Fraga, R. S. Pessoa, H. S. Maciel, M. Massi. Recent developments on silicon carbide thin films for
piezoresistive sensors applications. In: Moumita Mukherjee. (Org.). Silicon Carbide. Rijeka: Intech -
Open Acess Publisher, 2011, v. 1, p. 369-388.
A. Yamamoto, N.Norio, T. Takahiro. Evaluation of diamond gauge factor up to 500 °C Diamond &
Related Materials 16, 2007, 1670–1675.
A. Yamamoto, N. Nawachi, T. Tsutsumoto, A.Terayama. Pressure sensor using p-type polycrystalline
diamond piezoresistors Diamond & Related Materials 14, 2005, 657–660.
M.Deguchi, N. Hase, M. Kitabatake, H. Kotera, S. Shima, M. Kitagawa. Piezoresistive property of CVD
diamond films. Diamond and Related Materials 6, 1997, 367-373.